托福听力

🎧 听力原文

Listen to part of a lecture in a biology class. The professor is discussing the behavior of a particular insect species. Professor: Today, we're going to look at the social structure of ants, but specifically the leafcutter ant. These ants are fascinating because they don't actually eat the leaves they cut. Instead, they use the leaves to cultivate a fungus, which serves as their primary food source. This mutualistic relationship is highly specialized. The ants provide the fungus with a steady supply of fresh plant material, and in return, the fungus produces nutritious structures called gongylidia, which the ants consume. Interestingly, the fungus is so dependent on the ants that it cannot survive in the wild on its own. Also, the ants have evolved a behavior to control a parasitic mold that can infect their fungus gardens. They produce antibiotics through specialized bacteria that live on their bodies. This relationship between ants, fungus, and bacteria is a prime example of a tripartite symbiosis, showing how complex interactions can arise in nature.